source: Examiner Aug 11, 2010
Anders Björkman is a structural engineer from France who became an early member of Richard Gage’s AE911Truth. He had previously given speeches in his country to people whose children had seen footage of the Trade Towers’ destruction and were worried that buildings could collapse from the top down. He reassured these parents that this couldn’t happen and posted his presentation on his web site where it gradually developed.
Björkman became a formal critic of the “Progressive Collapse” or “Piledriver” theory promoted by Dr. Zdenek Bazant, a consultant for the National Institute of Standards and Technology (NIST) in its work on 9-11. The Piledriver Theory basically posits that prolonged heating weakened the support columns of a single floor which caused the upper section to crush what was below it in a chain-reaction all the way to the bottom.
“I explained on my website that you cannot destroy a building by dropping the top on the bottom; you have to destroy it from the bottom,” Björkman said. “Then a lot of people criticized that and said, ‘But Dr. Bazant says the opposite, and he has written all these papers,’ so of course I looked at these papers, and said, ‘This Bazant is nonsense.’ But others said, ‘But he’s peer-reviewed. It has been published in a scientific journal—the Journal of Engineering Mechanics.’”
Björkman contacted Ross Corotis, the journal’s editor, saying Bazant was incorrect and asking if he could write a response to the article. Corotis said yes, so Björkman wrote what he called “a very simple article” and submitted it in early February to the journal. In June Corotis contacted Björkman and told him the intended to publish it, but first Björkman needed to sign a copyright agreement, which he immediately returned. In September Björkman contacted the journal to investigate the delay and was told Corotis was waiting for Bazant to submit “closure” or his response to Björkman’s response. Björkman’s article and Bazant’s response were finally published in July of 2010.
Björkman explains why he vigorously disputes Bazant’s “Piledriver” idea.
“If you have a structure—anything, building blocks, Lego, or a book case, and you take the top part and drop it on the rest—because it’s the same structure—the smaller top part can never supply sufficient energy to destroy the bigger bottom—as long as it’s the same structure. If you have a solid steel ball on a lot of glass or very weak things, of course the strong one can crush the bottom part, but if the structure is the same –like the World Trade Center towers—the top part is weaker than the rest and can never crush anything below,” he said. “Fires cannot cause structural failures that make steel structures collapse from top down! It is quite basic, actually,” he said.
In his closure Bazant writes, “The discusser’s interest is appreciated. However, he presents no meaningful mechanics argument against the gravity driven progressive collapse model of our paper. His claim that “the authors’ theory is wrong” is groundless.” Bazant’s Closure
Bazant argues that differential equations are necessary in producing a realistic model of the collapses whereas Björkman thinks they are unnecessary—a simple model is all that is required. Bazant’s closure also repeats his endorsement of the “Crush Down” or “Progressive Collapse” theory he originally produced in 2001. On his web site Björkman posted a comment regarding Bazant’s “closure” saying, “[Bazant’s] Closure must be regarded as the most shameful Closure in structural damage analysis history!”
Björkman criticizes Bazant, as well as his theory, in strong terms. “I think he is a criminal. You can quote me because I’ve already said that on my web site,” he said. “This guy is a Lysenko-type scientist. He’s presenting a false theory for whatever purpose. I don’t know why he does it.”
Bazant’s theory, which Björkman dubbed the “Pouff Pouff Theory,” can be seen in the following graphic:
|The Pouff! Pouff! Theory|
From Björkman’s web site:
“I call it the POUFF, POUFF-theory. It was launched by the US National Institute of Standards and Technology, NIST, in its so called 911-report, where it is said that when … the release of potential energy due to downward movement of the building mass above the buckled columns (the upper part C up top) exceeded the strain energy that could be absorbed by the structure (parts A below), global collapse ensued.
The POUFF, POUFF-theory is illustrated below: The upper part C is originally carried by four parts A below. Then upper part C is given downward motion due to gravity (some supports between parts C and A are buckled) and upper part C applies, when impacting A, released potential energy on the top part A that is crushed down into rubble B – POUFF!
Then the rubble B is accelerated by the upper part C and gravity and more released potential energy is applied on the next part A that is crushed into more rubble B – another POUFF!
The crushing down will be repeated as many times as is required to crush all parts A into rubble B. Then the rubble B crushes up upper part C into more rubble B – the final POUFF!
My contribution is to name it POUFF, POUFF!”
Björkman is so confident in his criticism of Bazant that in March he created The Heiwa Challenge. He offers ten thousand Euros to anyone who can reproduce, within specified parameters, the progressive collapse theory on their own structures.
He notes that as of July 2010, no one has claimed the prize.